ISSN: 2949-401X

VOL. 2, NO, 1, 2024

Apr 15, 2024
Features of throwing the shell of a cylindrical shaped charge towards the axis

Guskov A. V., Potanina E. Yu.

A cylindrical shaped charge is a hollow cylindrical shell surrounded by an explosive substance. The process of jet formation in cylindrical cumulation is difficult to achieve, but it is of interest to researchers due to its features: the high velocity of the cumulative jet and the low gradient of the jet velocities along the length relative to the classical cumulation. To achieve a stable jet formation process, a two-stage cylindrical charge device is proposed in the work. The principle of its operation is based on the creation of a recompressed detonation mode in an internal explosive charge. Thus, the velocity of the inner shell throwing towards the axis will increase, which will lead to an increase in the angle of collapse of the shell and an improvement in jet formation. The paper presents a mathematical model of the functioning of such a device and considers several variants of such shaped charges. From a mathematical point of view, the possibility of functioning of such a device in the mode of recompressed detonation is proved.

Ryabinin A. N., Danilov A. V.

The rotational oscillations of a square prism mounted on a spring suspension in the test section of a low-speed wind tunnel are studied. The ratio of the length of the prism to the transverse size is 2.6. The prism can oscillate around the axis passing through the center of the prism and perpendicular to the velocity vector of the incoming flow and the longitudinal axis of the prism. The longitudinal axis of the prism in an equilibrium position is directed along the velocity vector of the incoming flow, or forms a small angle with it. An accelerometer GY-521 based on the MPU 6050 chip is used to register oscillations, it is connected to the Piranha UNO patronymic controller, which is an analog of the widespread Arduino UNO controller. In the absence of a flow, the rotational oscillations of the prism are damped. If the flow velocity is greater than a certain value, oscillations with a constant amplitude occur. The amplitude rises with an increase in the velocity of the incoming flow. The mathematical model proposed earlier to describe the rotational vibrations of the cylinder works satisfactorily to describe the oscillations of the prism.


Chernyshov M. V., Savelova K. E.

We considered branched shock-wave structures (triple configurations of shock waves) which forms in supersonic flows of perfect gas, mainly at high flow Mach numbers and low values of the adiabatic index. Ambiguity of the solution for triple configurations of steady shock waves formed at Mach reflection, including for configurations with a negative slope angle of the reflected shock, was studied analytically and numerically. The conditions for the coexistence of triple configurations which correspond to Mach reflection with other shock-wave structures are derived and graphically demonstrated.

Bulat P. V., Vokin L. O., Volkov K. N., Nikitenko A. B., Prodan N. V., Renev M. E.

The combustion chamber is one of the main components that determine the energy and mass characteristics of the propulsion system. A detailed description of the combustion chambers of some model engines running on kerosene is given. The results of fire tests and numerical studies of combustion chambers of model small-sized gas turbine engines are considered. To qualitatively compare the results of calculations with the data of a physical experiment, annealed colors are used. Based on the results of the research, a map of tem perature distribution on the walls of the combustion chamber was compiled. The internal and external surfaces of the combustion chamber are unevenly colored with tarnished colors. This coloring is a consequence of non-uniform distributions of temperature and concentration of various components of combustion products, and also indicates the formation of a spatial flow in the combustion chamber.

Vashchenko A. N., Grigoriev M. N., Zihan Zhang

The purpose of this article is to review the development and use of aircraft with traction electric motors based on the experience of the People’s Republic of China. Examples from the end of the XIX century to the present day are considered. The possibilities of cooperation between the two countries in the area of development and application of aircraft with traction electric motors are proposed, by increasing the efficiency of EMs and reducing their weight through the use of high-temperature superconductors that transition to a state of superconductivity at a temperature provided by liquid nitrogen at the level of 70–90 K.

Andryushkin A. Yu., Bulygin V. V., Zhenning Li

The reliability of aircraft is ensured by various functional coatings applied to them. The quality indicators of coatings are determined by the capabilities of the control system for the technological complex of their spraying. The control system is effective if, with a large number of input parameters, it adopts the optimal technological solution to achieve the set values of coating quality indicators. The use of fuzzy logic in the control system of the technological complex of coating spraying is proposed. Using the Fuzzy Logic Toolbox package of the MATLAB program, an analysis of the fuzzy logic-based control system for the technological operation of applying a sprayed composition to a coated surface was carried out. It is shown that the use of fuzzy logic as an element of artificial intelligence is effective in the control system of the technological spraying process.

Vasilkov D. V., Alexandrov A. S., Golikova V. V.

Model technological solutions for ensuring the quality of products during turning processing are proposed. A study of the workability of materials based on the ISO classification was carried out. To clarify the workability group, the MS code system was used, which allowed not only to clarify the workability group and the terms of delivery of the workpiece, but also to determine the specific cutting force. Based on the classifier-handbook, the parameters of the prefabricated cutting tool were selected and the technological modes for the prescribed processing conditions were determined. Based on the obtained specific cutting force, an algorithm for simplified determination of the cutting force is implemented. A study of the vibrations of the technological machining system was performed, which made it possible to formulate dynamic models for the system as a whole, subsystems of the workpiece and cutting tool. In relation to the dynamic model of the workpiece subsystem. The model has been simplified. A dynamic cutting characteristic was constructed, which made it possible to build an autonomous dynamic model of the technological system. In relation to this model, parameterization was performed, which made it possible to determine the stiffness coefficients of the fixed workpiece, as well as the inertia and dissipation coefficients. In relation to the selected processing conditions, the accuracy and roughness of the treated surface were checked. A study of the stability of the technological system of mechanical processing based on the algebraic Hurwitz criterion is carried out. In the general formulation, the Hurwitz determinant and stability conditions are obtained. The performed complex of calculations showed that the conditions determined by the Hurwitz stability criterion are met. This indicates that when processing in the selected modes, quiet cutting is carried out, which ensures the requirements for the quality of the product. The construction of the stability boundary can be performed in the space of variable technological parameters using the D-partitioning method or based on the R. Loeb algorithm. As a result of constructing the stability boundary in the space of variable parameters, the area of permissible technological modes is highlighted, which is the basis for solving the problem of processing control in accordance with the formed efficiency criteria. The complex of technological solutions presented in the article was deployed and implemented in relation to the turning of coating discs, as well as discs of turbines and compressors of gas turbine engines.

Zakharova A. O., Khrapko N. N., Patrusheva T. N., Petrov S. K.

The problem of creating antimicrobial protection methods in rocket and space technology requires new approaches, in particular, the development of antibacterial coatings to protect the payload of launch vehicles. Also, in outer space outside the Earth’s atmosphere, ultraviolet radiation with a wavelength of less than 280 nm (hard and vacuum ultraviolet) accelerates degradation of materials. It is relevant to create protective coatings for various materials used in space. An innovative extraction-pyrolytic method for producing oxide films containing copper, titanium and titanium oxide nanoparticles is considered. As a result, the compositions of effective antibacterial coatings with the function of protection against UV radiation have been established. The intended service and design features of the part on which the coating is applied are considered, and a flow diagram for applying an antibacterial coating to protect the internal volume of the fairing from bacteria circulating in the head of the launch vehicle is proposed. The possibilities of protection against UV radiation by applying oxide films to the outer surface of devices and rocket parts have been studied.

Shaidurova G. I., Vasiliev I. L., Shevyakov Ya. S., Tokareva M. I., Shakirova O. V.

The article presents the results of studies of epoxy binders and a comparative analysis of variant versions of basic formulations of synthetic resins and formulations modified with colloidal silicon dioxide and ultrafine zinc. The studies were carried out by instrumental methods using optical microscopy and differential scanning calorimetry, while the distribution of modifier nanoparticles in the volume of polymer matrices and their effect on the formation of the structure of cured binders were studied.

Zimin B. A., Kabanov D. S., Kabanov S. A., Mitin F. V., Nikulin E. N.

The article discusses the issue of using optimal control algorithms to minimize bending vibrations of the spoke of a large-sized transformable reflector in the process of its deployment. This reduces transient time and improves the reliability and safety of the antenna deployment process. The creation of large-sized space-based systems is a current trend. Such systems allow solving a wide range of problems related to monitoring the Earth’s surface and space. At the same time, due to their size, the issue of structural defor-mation arises. A mathematical model is presented that describes the process of deployment the spokes taking into account transverse vibrations. Optimal control algorithms have been developed to minimize structural vibrations. For the stage of adjusting the radio-reflective net, an algorithm has been developed that minimizes energy costs. The results are confirmed by mathematical modeling and testing of algorithms on a laboratory unit. A method for adjusting a radio-reflective surface has been proposed, which makes it possible to reduce the number of actuators while maintaining the number of actuation points.

Vinnik P. M., Vinnik T. V.

The paper deals with condition of global stiffness matrices of regular mesh of finite elements. The estimation from above the greatest eigenvalue of such matrix offeres. The estimation is under construction on a local stiffness matrix of any finite element, hence, depends only from the size and the form of such element and does not depend on quantity of the final elements making a regular grid. At estimation construction the Gerschgorin’s theorem and that fact are used that local matrixes of rigidity of final elements of regular grids differ from each other only shift of blocks. On a numerical example it is shown that the constructed estimation possesses split-hair accuracy and at a considerable quantity of the elements entering into a grid, it is possible to consider it almost coinciding with the greatest own number. The behaviour of an estimation is shown at change of quality of the form of final elements.

R. V. Melnikov, S. M. Stazhkov, V. S. Elchinsky, S. S. Negashev

The influence of water content in hydraulic fluids on their viscosity and temperature properties is considered. It is substantiated that a change in the viscosity of mineral oils with a change in water content can lead to both an increase in viscosity and a decrease in it. The results of an experimental determination of the viscosity of mineral oil mixed with a seawater simulator are presented. It is indicated that models of non-Newtonian fluids can be used to describe the behavior of the mixtures under consideration.